This invention relates to data input devices, and more particularly, provides a master controller which may be used for directing movements of a robot and which is particularly useful for robotically enhanced surgery.
In robotically assisted surgery, the surgeon typically operates a master controller to remotely control the motion of surgical instruments at the surgical site. The controller may be separated from the patient by a significant distance (e.g., across the operating room, in a different room, or in a completely different building than the patient). Alternatively, a controller may be positioned quite near the patient in the operating room. Regardless, the controller will typically include one or more hand input devices such as a joystick, exo-skeletol gloves, or the like. These hand input devices are coupled by a servo mechanism to the surgical instrument. More specifically, servo motors move a manipulator or xe2x80x9cslavexe2x80x9d supporting the surgical instrument based on the surgeon""s manipulation of the hand input devices. During an operation, the controller may employ, via the robotic surgery system, a variety of surgical instruments such as tissue graspers, needle drivers, electrosurgical cautery probes, etc. Each of these structures perform functions for the surgeon, for example, holding or driving a needle, grasping a blood vessel, or dissecting, cauterizing, or coagulating tissue.
To deliver the full potential of this promising new form of surgery, the robotic system will preferably allow movement of the end-effector in both position and orientation. Directing such robotic input is much easier when the surgeon is able to move the hand input device with motions that correspond to the desired motions of the end-effector. Hence, it would be desirable to provide hand input devices which can move in three-dimensional space, and which can also change in orientation about three axes. While a variety of robotic input devices have been proposed, including known force reflecting input devices, exo-skeletal input devices, and the like, these proposed devices have generally had shortcomings, particularly when the system operator desires to manipulate an input device to direct a wide range of end-effector motions such as those that can be imparted when a surgeon""s hand manipulates a surgical tool, repositions her hand on the handle of the tool, or the like.
Unfortunately, mechanical linkage systems of known hand input devices do not provide unlimited freedom of movement. In fact, linkage systems for both the slave and the master controller will typically have xe2x80x9csingularitiesxe2x80x9d. These singularities are linkage configurations in which motion of the linkage is inhibited in at least one direction. Singularities can occur, for example, when two of the pivotal or other axes of motion of the linkage system become aligned, so that they no longer independently contribute to the mobility of the mechanism. Such binding or loss of motion capability of the master and/or slave linkage systems is disadvantageous during robotically assisted surgery.
In minimally invasive robotic surgery procedures, the surgical end effectors will typically be introduced through a small incision or opening into an internal surgical site. To position and orient the end-effector in the internal surgical site, the end-effectors will often be supported at the end of elongate shafts, with one or more joints disposed between the shaft and the end effector. Hence, the linkage systems supporting the end effector may be quite different that the linkage supporting the hand input device of the master controller. Additionally, the surgical end effectors which access the internal surgical site through an opening will often be removed and replaced during surgery. For example, needle graspers may be replaced by a scalpel. It would generally be desirable to avoid and/or decrease loss of mobility due to master singularities and the like, regardless of the specific end effector in use.
In light of the above, it would be desirable to provide improved input devices, robotic surgical apparatus, and robotic methods.
The present invention provides an input device and method which is particularly useful for robotically-enhanced surgical techniques. The robotic input device (often called a master controller) has a handle supported by a linkage so that the handle can move in space, ideally so that the handle can turn in any orientation. The linkage includes a redundant degree of freedom. At least one joint of the linkage may be actively driven by a processor of the robotic system to prevent the linkage from approaching singularities. In the exemplary embodiment, the master includes an arm assembly which is used primarily to position the handle in the controller workspace. The arm provides three degrees of freedom, and is coupled to the handle by a wrist system having four degrees of freedom. One or more additional degrees of freedom may also be provided for actuation of the handle, for example, to close the jaws of a surgical grasper. Hence, the master may have a total of eight or more degrees of freedom (including end effector actuation).
Work in connection with the present invention has shown that it is not always possible and/or desirable that the master and slave have singularities that correspond. If a robotic surgical system uses a master and slave which are kinematically dissimilar, it is unlikely that the singularities of the master will occur at the same position as those of the slave. Hence, the total number of singularities affecting the system includes those of both the master and those of the slave, as the singularities of the master may prohibit otherwise possible slave motions. The redundant degree of freedom of the master controller described herein can provide a usable workspace with fewer (or even no) singularities to reduce these limits on the system""s movement.